Molding tool and method for producing a molding tool for extruding cellulose molded bodies

ABSTRACT

The invention relates to a molding tool ( 1, 51 ) for the extrusion of cellulosic molded bodies ( 4 ) from a spinning dope ( 2 ), having an entry side ( 6, 56 ) and an exit side ( 7, 57 ) for the spinning dope ( 2 ), with at least one nozzle body ( 8, 58   a,    58   b,    58   c ) including a planar carrier ( 9, 59   a,    59   b,    59   c ) with extrusion openings ( 10, 60 ) that penetrate the carrier from the entry side ( 6, 56 ) to the exit side ( 7, 57 ) and have a mouth diameter ( 12, 62 ) at the exit side ( 7, 57 ) and through which the spinning dope ( 2 ) is extruded into the cellulosic molded bodies ( 4 ). In order to provide a molding tool of the afore-mentioned type, which is easier and more inexpensive to manufacture while providing excellent strength and pressure stability at the same time, it is proposed that the ratio of the thickness ( 13, 63 ) of the carrier ( 9, 59   a,    59   b,    59   c ) to the mouth diameter ( 12, 62 ) of the extrusion openings ( 10, 60 ) at the exit side ( 7, 57 ) be at least 6:1, preferably at least 10:1, and that the extrusion openings ( 10, 60 ) be formed in the carrier ( 9, 59   a,    59   b,    59   c ) by applying laser energy.

FIELD OF THE INVENTION

The invention relates to a molding tool for the extrusion of cellulosicmolded bodies from a spinning dope, having an entry side and an exitside for the spinning dope, with at least one nozzle body including aplanar carrier with extrusion openings that penetrate the carrier fromthe entry side to the exit side and have a mouth diameter at the exitside and through which the spinning dope is extruded into the cellulosicmolded bodies.

The invention also relates to a method for producing the molding tooland to a method for producing cellulosic molded bodies by using themolding tool.

BACKGROUND OF THE INVENTION

Typically, molding tools used for the extrusion of cellulosic moldedbodies of the afore-mentioned type (also known as “spinning nozzles” or“spinnerets”) must meet numerous high quality criteria in order to besuited for spinning of highly viscous cellulose solutions. For instance,high standards with respect to the quality and dimensional accuracy(profile shape, mouth diameter, and positioning) of the extrusionopenings must be satisfied in order to obtain a homogeneous bundle ofmolded bodies and avoid any sticking together of the individual moldedbodies in the bundle of molded bodies. Furthermore, the roughness of theinner walls of the extrusion openings as well as the edge sharpness andfreedom from burrs of the extrusion openings play a crucial role inshaping the molded bodies (that are formed from the extruded spinningdope at the exit side of the extrusion opening) and in avoiding spinningdefects (such as breaking, tearing, or sticking together of moldedbodies) caused, for example, by irregularities or burrs of the extrusionopenings at their exit side. High standards must also be satisfied interms of the strength of the molding tools, as they are exposed to veryhigh pressures of up to 150 bar during the extrusion of the spinningdope.

From EP 0 430 926 B1 and WO 94/28211 A1, molding tools for the extrusionof cellulosic molded bodies from a spinning dope are known, which can beused in methods for producing cellulosic molded bodies—such as theviscose or lyocell processes. In these cases, the extrusion openings aretypically formed in a carrier by means of mechanical drilling orpunching. However, this presupposes that the material of the carriermeets special requirements, as it must have sufficient ductility, on theone hand, so that it can be machined with the drilling or punching tool,and must permanently withstand the very high pressures of up to 150 barin the viscose or lyocell process, on the other. In EP 0 430 926 B1,these requirements are met, for example, by inserting a small plate madeof a softer, easy-to-machine material (such as gold, silver, ortantalum), in which the extrusion openings have been formed, into astainless steel carrier. The special combination of materials makes iteasy to form the extrusion openings in the molding tool and yet obtain ahigh level of strength. However, such molding tools have thedisadvantage that the materials used for them are very expensive andthat the composite molding tools require a high-effort manufacturingprocess, as the small plates need to be inserted into and connected tothe carrier at a subsequent stage. Furthermore, mechanical machiningprocesses such as drilling or punching create burrs at the extrusionopenings, which need to be removed in additional effortful finishingsteps (e.g., by polishing). Also, such mechanical machining processesare able to achieve only limited positioning accuracy andreproducibility, which will generally result in large tolerances at theextrusion openings.

WO 2005/005695 A1 shows a method for producing molding tools of theafore-mentioned type, the extrusion openings being formed in a carrierof the molding tool by means of electron beams. Molding tools producedin such a manner solve the problem of the choice of materials, as theextrusion openings can be formed directly in the carriers, whereby theseparate formation of extrusion openings in a small plate and theeffortful subsequent assembly of the components become unnecessary. Inaddition, such extrusion openings formed in the molding tools by usingelectron beams exhibit advantageously reduced roughness and high edgesharpness with minimal burr. Yet, the extrusion openings formed in thecarrier by using electron beams are highly limited in their profileshapes and have a high variation or tolerance regarding their mouthdiameters, as the effect of the electron beams can be controlled andreproduced only to a limited extent. In addition, the formation of theextrusion openings by using electron beams must take place in a highvacuum, which in turn implies an effortful manufacturing method.

DISCLOSURE OF THE INVENTION

Therefore, it is an object of the invention to provide a molding tool ofthe afore-mentioned type, which can be produced more easily andinexpensively while also offering excellent strength and pressurestability, and whose extrusion openings have smaller tolerances inregard to mouth diameter, position, and profile shape.

The invention solves the defined object in that the ratio of thethickness of the carrier to the mouth diameter of the extrusion openingsat the exit side is at least 6:1 and that the extrusion openings areformed in the carrier by applying laser energy.

If the ratio of the thickness of the carrier to the mouth diameter ofthe extrusion openings at the exit side is at least 6:1, then aparticularly pressure-stable nozzle body of high strength can be createdwhich guarantees a long service life at high pressure. This pressurestability means that plastic deformations of the nozzle body during itsservice life can be avoided under normal operating conditions, whereas asmall amount of load-dependent elastic deformations is unavoidable. Thisstrength can be improved further if the above-mentioned ratio is atleast 10:1, or more preferably at least 12:1 or at least 15:1.Furthermore, if the extrusion openings are formed in the carrier byapplying laser energy, then the molding tool can prove advantageous bybeing very easy to manufacture. In this case, the extrusion openings canbe formed in the carrier of the molding tool with very high dimensionalaccuracy, whereby a molding tool can be created that meets the highquality requirements and narrow dimensional tolerances in regard tomouth diameter and positioning. In particular, the use of laserradiation makes it possible to obtain dimensional tolerances of lessthan 2% for the critical parameters such as mouth diameter, holegeometry and cross-section of the extrusion openings, as well asdistance between the extrusion openings. The laser radiation also makesit possible to directly create smooth and burr-free extrusion openings,as a consequence of which further finishing steps on the molding toolcan be omitted. Such finishing steps such as grinding or polishinginvolve high mechanical loads and can generate adverse stress effects inthe carrier. It is therefore possible to create a molding tool withsmall dimensioning tolerances that is particularly easy to manufactureand reliable.

Within the scope of the invention, the term ‘molded bodies’ particularlydenotes the filaments exiting the extrusion openings, which cansubsequently be used for the production of continuous or staple fibers.Within the scope of the invention, such filaments or fibers preferablyhave titers greater than or equal to 0.7 dtex.

Generally, it is noted that the invention relates to molding tools forthe production of regenerated cellulose molded bodies, having a mouthdiameter of the extrusion opening at the exit side of greater than orequal to 40 μm, particularly of greater than or equal to 45 μm,preferably of greater than or equal to 50 μm, more preferably of between70 μm and 150 μm. If the mouth diameters are less than 40 μm, then themolding tools are particularly suited for the production of microfibershaving a fiber titer of less than 0.7 dtex. However, the molding toolsof the present invention are used in the production of cellulosic fiberstypically having a titer of greater than or equal to 0.7 dtex for whichextrusion openings having a mouth diameter greater than 40 μm aresuitable.

If the thickness of the carrier is at least 600 μm, then a molding toolfeaturing sufficient strength and service life of the nozzle body can becreated, which can also be designed large enough in order to provide foran advantageous production throughput. In particular, the preferredthickness of the carrier is at least 800 μm, and more preferably 1000μm. If the carrier has a thickness in this range, then it can be ensuredthat there will be no plastic deformation of the carrier in regularoperation, at operating pressures up to 100 bar that are usuallyencountered, for example, in a method for producing regeneratedcellulose molded bodies of the lyocell type (lyocell process). Afterall, plastic deformation of the carrier can adversely alter the geometryof the extrusion openings and also negatively influence the dischargebehavior of the molded bodies from the molding tool. In addition, it canbe ensured that the carrier can even be loaded with a pressure of up to150 bar in overpressure events without causing the carrier to break orsuffer irreversible structural damage. Molding tools including a carrierwith a thickness of less than 600 μm are only of limited suitability foruse in such methods, as they do not have the necessary strength in orderto permanently withstand the high pressures and allow only a verylimited throughput, respectively.

If the extrusion openings at the exit side are free from burrs, then amolding tool can be created in which detrimental sticking together ofthe molded bodies after exiting the extrusion openings can be avoided.After all, burrs at the extrusion openings can entail the disadvantagethat the extruded molded bodies will not exit the extrusion openings ina straight orientation, but be diverted by the burr and come intocontact and stick together with a neighboring molded body, therebycausing spinning defects that require an interruption and restart of theprocess (renewed spin-up) or lead to rejects being produced.

Particularly versatile molding tools for use in different methods forthe extrusion of cellulosic molded bodies can be created whenconfiguring the nozzle body as being of annular or rectangular shape. Inaddition, the molding tool can include several of such nozzle bodies.Thus, it is possible, for example, that the molding tool includesseveral rectangular nozzle bodies adjoining one another. Such a moldingtool, for example, is particularly easy to manufacture and can be morecost-effective.

If the molding tool has at least a first web firmly connected to thenozzle body by material bonding and protruding from the nozzle bodytoward the entry side, then the stability and strength of the carriercan be improved further, on the one hand, as the web counteracts apressure load of the nozzle body and especially of the carrier, and theweb provides a guide surface for the spinning dope, on the other hand,as it can ensure the efficient transport of the spinning dope to theextrusion openings. In addition, suitably configuring the web helpsavoid the formation of dead spaces and thus improves the quality of themolded bodies extracted thereby.

The strength of the carrier can yet be substantially increased, if themolding tool has at least a second web, the nozzle body extendingbetween the first web and the second web. Like the first web, the secondweb is firmly connected to the nozzle body by material bonding andprotrudes from the nozzle body toward the entry side. Thus, the firstand second webs can particularly serve as edge-side support of thenozzle body and thus reliably absorb the pressure loads acting on thecarrier during the extrusion. In addition, the first and second webstogether can form a passage for guiding the spinning dope at the entryside. This way, a particularly reliable and durable molding tool can becreated.

The molding tool can prove particularly advantageous if at leastportions of the web extend substantially normal to the nozzle body. Dueto the part that extends substantially normal to the nozzle body, thespinning dope can be directed heavily toward the extrusion openings, anda directional mass flow can thus be maintained.

If the distance normal to the lengthwise extension of the nozzle bodybetween the first and second webs is at least less than 100 times thethickness of the carrier, then the molding tool will be able to proveeffective through excellent stability and resistance against deformationby the high pressure of the spinning dope.

Advantageously, the first web can fully encircle the second web and thusprovide a molding tool of a particularly simple design. This can beparticularly suited, for example, for use in a molding tool having anannular nozzle body, the annular nozzle body in this case extendingbetween the first and second webs.

If, at the entry side, the molding tool also includes a flange with atleast one flange limb, the flange limb adjoining the web, then aneasy-to-handle and flexible-to-replace molding tool can be created whichcan be attached fast and easily to a spinning machine via the flange. Ifthe flange limb protrudes outward from the molding tool, then it canalso be ensured that the spinning dope can flow freely, withoutimpediments, from the entry side to the nozzle body, thereby ensuringuniform extrusion by the molding tool.

As regards the method for producing the molding tool as claimed in oneof claims 1 through 11, the object of the invention is to provide asimple and cost-effective method which nevertheless achieves highprecision.

The object regarding the production method is solved by thesubject-matter of claim 12.

If a molding tool is produced according to one of claims 1 through 11,in which the extrusion openings are formed in the carrier by applyinglaser energy thereto from the entry side of the molding tool andburr-free extrusion openings are created in the carrier without anyfurther finishing at the exit side, then a particularly simple andreproducible production method for molding tools can be created. Byusing laser radiation, the effortful finishing of the extrusion openingsbecomes obsolete as well, as the extrusion openings directly formed inthe carrier are able to meet all quality criteria required of themolding tools. This is true for the roughness and freedom from burrs ofthe extrusion openings as well as for the positioning accuracy andopening diameter. If the laser energy is applied to the carrier in theform of pulsed laser radiation, then particularly small manufacturingtolerances of the extrusion openings can be met. Laser radiation with apulse duration between 100 fs and 100 ns and pulse energies between 1 μJand 1000 μJ has proved particularly suitable. In this connection, thepulsed laser radiation can preferably be applied to the carrier in apercussion drilling process or a helical drilling process and thuscreate extrusion openings with high precision and small manufacturingtolerances.

If the extrusion openings are formed in the carrier after the carrierhas been firmly connected to a web by material bonding, then aparticularly reliable and reproducible manufacturing method can beprovided. The creation of a firm material bonding connection between thecarrier and a web inexorably subjects the carrier material to mechanicalloads and thus leads to an undesired deterioration or alteration of theextrusion openings. By subsequently forming the extrusion openings inthe completely assembled or completed formed molding tool, suchmechanical loading of the extrusion openings can be avoided, especiallyif forming of the extrusion openings takes place as the last, finalprocedural step.

The molding tool according to the invention as claimed in one of claims1 through 11 can prove particularly advantageous when used in a methodfor producing regenerated cellulose molded bodies whereincellulose-containing spinning dope is extruded by the molding tool andprecipitated in a spinning bath in order to produce the molded bodies.

Preferably, such a method can be a lyocell process wherein the spinningdope contains a tertiary amine oxide in which the cellulose is dissolvedand the spinning bath includes a mixture of water and tertiary amineoxide.

SHORT DESCRIPTION OF THE DRAWINGS

The embodiments of the invention are described hereinafter withreference to the drawings, wherein:

FIG. 1 is a sectional view along I-I of FIG. 2 of a molding toolaccording to a first embodiment,

FIG. 2 is a plan view of the molding tool of FIG. 1,

FIG. 3 is a torn-away sectional view along II-II of FIG. 4 of a moldingtool according to a second embodiment,

FIG. 4 is a plan view of the molding tool of FIG. 3, and

FIG. 5 is a partially torn-away sectional view of a spinning machinewith an inventive molding tool of FIG. 1.

MODES OF CARRYING OUT THE INVENTION

FIG. 1 shows an annular molding tool 1 according to a first embodimentof the invention, which is used in a spinning device 100 of FIG. 5 andin a method for the extrusion of cellulosic molded bodies 4. The moldingtool 1 has an entry side 6 for the spinning dope 2 and an exit side 7for the extruded spinning dope 3 (cf. FIG. 5). In addition, a nozzlebody 8 with a planar carrier 9 is provided in the molding tool 1. Inthis case, the nozzle body 8 can be integrally formed with the remainingmolding tool 1 (for example, by deep drawing, milling, etc.) or befirmly connected to it by material bonding in another way (for example,by welding, etc.).

The carrier 9 includes extrusion openings 10 that penetrate it from theentry side 6 to the exit side 7. At the exit side 7, the extrusionopenings 10 form a mouth 11 having a mouth diameter 12. In this case,the size of the mouth diameter 12 decisively influences the titer (ordiameter) of the extruded cellulosic molded body 4. In addition, theextrusion behavior and the geometry of the molded bodies 4 can becontrolled via the cross-sectional shape of the extrusion opening 10.For example, this can be used to change the discharge behavior of thespinning dope 2 from the extrusion openings 10 in order to preventsticking together of the extruded spinning dope 3 prior to precipitationin the spinning bath 5. In this case, preferred cross-sectional shapesof the extrusion openings 10 may have a configuration that is taperingtoward the exit side 7, as is shown in FIG. 1. However, thecross-sectional shape can be arbitrarily varied by laser radiation sothat, for example, hourglass-shaped configurations widening toward theexit side 7 are possible.

The extrusion openings 10 have a mouth diameter 12 between 70 and 150μm. Such mouth diameters 12 can ensure that fibers or filaments having atiter greater than 0.7 dtex are produced as the extruded cellulosicmolded bodies 4. In another preferred embodiment of the invention,regenerated cellulose fibers having a titer between 1.0 and 2.5 dtex areproduced.

The ratio of the thickness 13 of the carrier 9 to the mouth diameter 12of the extrusion opening 10 is at least 6:1, thereby ensuring sufficientresistance of the carrier 9 to the high pressures exerted by thespinning dope 2. In further preferred embodiments of the invention, aratio of at least 10:1, of at least 12:1, or of at least 15:1, ischosen.

The thickness 13 of the carrier 9 is at least 600 μm. This way, thecarrier 9 is able to permanently withstand a pressure load of up to 150bar from the entry side 6. In another embodiment, the preferredthickness 13 of the carrier 9 is at least 800 μm, or preferably 1000 μm,in order to ensure a particularly high resistance of the carrier 9.

The extrusion openings 10 were formed in the carrier 9 by applying laserenergy to it, and allowing laser energy to act on it. This makes it easyto produce the molding tool 1 in technical processes. In addition, withthe laser radiation acting on the material of the carrier 9,particularly high dimensional accuracy in the positioning, thedimensions, and the geometry of the extrusion openings 10 is achieved.In particular, the extrusion openings 10 have a constant averagedistance 14 from one another that is between 50 and 1000 μm, thestandard deviation of the distance 14 being no more than 1%. In order toavoid sticking together of the fibers as they exit the extrusionopenings 10, larger distances 14 from 250 to 800 μm are usuallyemployed. In this connection, the extrusion openings 10 can be disposedas distributed over the carrier 9 in an arbitrary, regular pattern(e.g., radial, grid-shaped, etc.) or irregularly. Also, the laserradiation makes it possible to obtain a standard deviation of the mouthdiameters 12 of less than 2%. In addition, the extrusion openings 10formed in the carrier 9 by using laser radiation do not have burrs atthe exit side 7 right after being formed and thus do not have to besubjected to any further finishing steps such as grinding or polishingwhich might adversely affect the geometry of the extrusion openings 10.In particular, the burr-free and smooth extrusion openings 10 alsoensure that the individual strands of the extruded spinning dope 3 willnot stick together before being precipitated into the molded bodies 4 inthe spinning bath 5.

The molding tool 1 shown in FIGS. 1 and 2 and having an annular nozzlebody 8, includes a first web 15 and a second web 16, both of which arefirmly connected to the annular nozzle body 8 by material bonding. Thus,the webs 15, 16 can, for example, be integrally formed with the carrier9 of the nozzle body 8, for example in that the molding tool 1 isconfigured as deep drawn or milled in one piece, or be firmly connectedto it by material bonding, for example, by welding. In this case, theannular nozzle body 8 extends between the first and second webs 15, 16.The webs 15 and 16 protrude from the nozzle body 8 toward the entry side6. Due to the firm material bonding connection to the nozzle body 8, thewebs 15, 16 act as an edge-side support of the carrier 9, whereby it isable to withstand a higher pressure load by the spinning dope 2. Due tothe annular configuration of the nozzle body 8, the first web 15 fullyencircles the second web 16 and the nozzle body 8. Thus, the two webs 15and 16 always extend parallel to one another and maintain a constantnormal distance 17 transversely to the lengthwise extension 18 of thenozzle body 8, along the carrier 9, from one another. In this case, thenormal distance 17 is no more than 100 times the thickness 13 of thecarrier 9 in order to ensure the maximum stability of the nozzle body 8.

In the interior of the molding tool 1, the webs 15 and 16 act as guidesurfaces 19 for the spinning dope 2, which advantageously support theflow behavior of the highly viscous spinning dope 2 and prevent theformation of dead spaces within the molding tool 1. Thus, the webs 15,16 form a guide passage 20 for the spinning dope 2 starting from theentry side 6. Preferably, the webs 15 and 16 extend, as shown in FIG. 1,normally to the nozzle body 8 and thus normally to the carrier 9.

In addition, the molding tool 1 includes a flange 23 by means of whichthe molding tool 1 can be—as is shown in FIG. 5—connected to a spinningdevice 100. In this case, the flange 23 includes two flange limbs 21,22, each adjoining the webs 15 and 16 at the entry side 6, and whichprotrude outward from the webs 15 and 16 and thus from the molding tool1. As such, the flange limbs 21, 22 do not obstruct the guide passage 20for the spinning dope 2 and thus reliably avoid having a negativeinfluence on the flow conditions in the guide passage 20.

FIGS. 3 and 4 show a molding tool 51 according to a second embodiment,which includes several rectangular nozzle bodies 58 a, 58 b, 58 c. Themolding tool 51 can be used in a spinning device 100 of FIG. 5 and in amethod for the extrusion of cellulosic molded bodies 3, just like themolding tool 1. Equivalent to the description for the first embodiment,the molding tool 51 includes an entry side 56 for the spinning dope 2and an exit side 57 for the extruded spinning dope 3 (cf. FIG. 5).

In this case, the molding tool 51 includes three nozzle bodies 58 a, 58b, and 58 c, each of which comprises a planar carrier 59 a, 59 b, 59 c.Generally, it is to be mentioned that a molding tool 51, as shown inFIGS. 3 and 4, need not be limited to three nozzle bodies. Rather, anyother number and arrangement of nozzle bodies in the molding tool ispossible.

In this case, the nozzle bodies 58 a, 58 b, 58 c are firmly connected tothe remaining molding tool 51 by material bonding, preferably by welds73. The carriers 59 a, 59 b, 59 c include respective extrusion openings60 which penetrate them from the entry side 56 to the exit side 57 andare formed in them through the action of laser radiation. At the exitside 57, each of the extrusion openings 60 forms a mouth 61 having amouth diameter 62. As described for the first embodiment, the mouthdiameters 62 can be varied in order to change the titer of the extrudedcellulosic molded bodies 4. The preferred mouth diameter 62 of theextrusion openings 60 is between 70 and 150 μm in order to producecellulosic molded bodies 4, particularly fibers, having a titer greaterthan 0.7 dtex. In addition, by forming the extrusion openings 60 bymeans of laser radiation, a standard deviation of the mouth diameters 62of less than 1% is obtained. More preferably, this is used to produceregenerated cellulose fibers having a titer between 1.0 and 2.5 dtex.Also, as described for the first embodiment, the cross-sectional shapesof the extrusion openings 60 can be changed in order to control the exitbehavior of the extruded spinning dope 3.

The carriers 59 a, 59 b, 59 c of the nozzle bodies 58 a, 58 b, 58 c havea preferred thickness 63 of at least 600 μm. In other advantageousconfigurations of this embodiment, the thickness 63 is at least 800 μm,or at least 1000 μm, in order to obtain a particularly permanentlyresistant molding tool 51 that withstands the high pressures of up to150 bar acting from the entry side 56. Here, the ratio of the thickness63 of the carriers 59 a, 59 b, 59 c to the mouth diameter 62 of theextrusion openings 60 is at least 6:1 in order to obtain the necessaryresistance. In preferred configurations of the invention, the ratio isat least 10:1, at least 12:1, or at least 15:1.

Very high dimensional accuracy in the positioning and the dimensions ofthe extrusion openings 60 is obtained by forming the extrusion openings60 in the carriers 59 a, 59 b, 59 c by applying laser energy to them. Asis shown in FIG. 4, the extrusion openings 60 are disposed at a constantdistance 64 of 50 to 1000 μm from one another, the standard deviationbeing no more than 2% of the distance 64. In addition, by using laserradiation, the extrusion openings 60 can be formed as essentiallyburr-free, which makes any further grinding or polishing stepsunnecessary and thus helps avoid the formation of stress effects in thecarriers 59 a, 59 b, 59 c.

The molding tool 51 includes first webs 65 a, 65 b, 65 c, 65 d, providedat the outside of the molding tool 51. Inside the molding tool 51 secondwebs 66 a, 66 b are provided that extend in a rib-like manner betweenthe first webs 65 c and 65 d and are firmly connected to them bymaterial bonding. In this case, each of the nozzle bodies 58 a and 58 cextends transversely to its lengthwise extension 68 between a first web65 a, 65 b and a second web 66 a, 66 b. The nozzle body 58 b extendsbetween the second webs 66 a, 66 b. The webs 65 a, 65 b, 65 c, 65 d, 66a, 66 b and the carriers 59 a, 59 b, 59 c of the nozzle bodies 58 a, 58b, 58 c are firmly material-bond-connected to one another via welds 73.Preferably, the webs 65 a, 65 b, 65 c, 65 d, 66 a, 66 b are configuredas one integral piece (for example, as a milled, deep-drawn, rolledpiece, etc.), and protrude from the nozzle bodies 58 a, 58 b, 58 ctoward the entry side 56.

The webs 65 a, 65 b, 66 a, 66 b extend parallel to one another andmaintain a constant normal distance 67 (normal to the lengthwiseextension 68) to one another along the carriers 59 a, 59 b, 59 c. Inthis case, the normal distance 67 is no more than 100 times thethickness 63 of the carriers 59 a, 59 b, 59 c so that the highestpossible stability of the nozzle bodies 58 a, 58 b, 58 c is obtained.

Inside the molding tool 51, the webs 65 a, 65 b, 65 c, 65 d 66 a, 66 bact as guide surfaces 69 for the spinning dope 2. Thus, the webs 65 a,65 b, 65 c, 65 d, 66 a 66 b create a guide passage 70 starting from theentry side 56, through which the spinning dope 2 is guided to theextrusion openings 60.

In addition, the molding tool 51 includes a flange 73, by means of whichthe molding tool 51 can be connected to a spinning device 100 in aforce-locking engagement. In this case, four flange limbs 71 a, 71 b, 71c, and 71 d, each of which adjoins a first web 65 a, 65 b, 65 c, 65 d,form the flange 73 which protrudes outward from the molding tool 51 atthe entry side 56 and encircles the molding tool 51.

FIG. 5 shows a spinning device 100 in which, according to a method forproducing regenerated cellulose molded bodies 4, a spinning dope 2 isextruded into the cellulosic molded bodies 4 through a molding tool 1according to the first embodiment of the invention. In order to obtainthe molded bodies 4, in such a method for producing regeneratedcellulose molded bodies 4, the extruded spinning dope 3 is—after theextrusion—guided through an air gap 8 into a spinning bath 5 where thecellulose precipitates from the extruded spinning dope 3. According toanother preferred configuration of the invention, the method forproducing the regenerated molded bodies 4 is a lyocell process whereinthe spinning dope 2 contains a solution of cellulose in a tertiary amineoxide. In this case, the spinning bath 5 for the precipitation of theextruded spinning dope 3 contains a mixture of water and a tertiaryamine oxide (for example, NMMO-N-methylmorpholine-N-oxide).

1. A molding tool for the extrusion of cellulosic molded bodies from acellulose-containing spinning dope comprising an entry side and an exitside for the cellulose-containing spinning dope, with at least onenozzle body including a planar carrier with extrusion openings thatpenetrate the carrier from the entry side to the exit side and have amouth diameter at the exit side and through which thecellulose-containing spinning dope is extruded into the cellulosicmolded bodies, wherein a ratio of the thickness of the carrier to themouth diameter of the extrusion openings at the exit side is at least6:1, and that the extrusion openings were formed in the carrier byapplying laser energy.
 2. The molding tool as claimed in claim 1,wherein the carrier has a thickness of at least 600 μm.
 3. The moldingtool as claimed in claim 1, wherein the extrusion openings are burr-freeat the exit side.
 4. The molding tool as claimed in claim 1, wherein theat least one nozzle body is annular or rectangular.
 5. The molding toolas claimed in claim 1, wherein the molding tool comprises several nozzlebodies.
 6. The molding tool as claimed in claim 1, wherein the moldingtool further comprises at least one first web which is firmly connectedto the at least one nozzle body by material bonding and protrudes fromthe at least one nozzle body towards the entry side.
 7. The molding toolas claimed in claim 6, wherein the molding tool further comprises atleast one second web, wherein the nozzle body extends between the atleast one first web and the at least one second web.
 8. The molding toolas claimed in claim 6, wherein at least portions of the at least onefirst web extend essentially normal to the nozzle body.
 9. The moldingtool as claimed in claim 7, wherein a distance normal to a lengthwiseextension of the at least one nozzle body between the at least one firstweb and the at least one second web is at least less than 100 times thethickness of the carrier.
 10. The molding tool as claimed in claim 7,wherein the at least one first web fully encircles the at least onesecond web.
 11. The molding tool as claimed in claim 6, wherein, at theentry side, the molding tool further comprises a flange with at leastone flange limb, the flange limb adjoining the web and protrudingoutward from the molding tool.
 12. A method for producing a molding toolas claimed in claim 1, comprising forming the extrusion openings in thecarrier by applying laser energy to it from the entry side of themolding tool, and creating at the exit side, burr-free extrusionopenings in the carrier without any further finishing.
 13. The method asclaimed in claim 12, further comprising as a final procedural step,forming the extrusion openings in the carrier.
 14. A method forproducing regenerated cellulose molded bodies, comprising extruding thecellulose-containing spinning dope through the molding tool as claimedin claim 1 and precipitating in a spinning bath in order to produce thecellulosic molded bodies.
 15. The method as claimed in claim 14, whereinthe cellulose-containing spinning dope comprises a tertiary amine oxidein which the cellulose is dissolved and the spinning bath includes amixture of water and tertiary amine oxide.
 16. The molding tool asclaimed in claim 1, wherein the ratio of the thickness of the carrier tothe mouth diameter of the extrusion openings at the exit side is atleast 10:1.
 17. The molding tool as claimed in claim 2, wherein thethickness of the carrier is at least 800 μm.